Manufacture of quinone



A. c. CARUS f MANUFACTURE OF QUINONE Nov. 15, 1938.

Filed Sept. 25, 1956 tion to such an Patented Nov. 15, 1938 UNITED STATES PATE NT OFFICE 2,136,966 MANUFACTURE or QUINONE Application September 1936, Serial No. 102,609 3 Claims. (Cl. 202-46) .E'nis method relates to the manufacture of quinone and other like substances in which the product is distilled from a reaction mass with steam. The distillation of quinone and other 'or-. ganic bodies by steam distillation has long been practiced, but in the preparation of quinone and certain other organic materials by steam there is a tendency for the quinone to condense and form a cake in the condenser which eifectively blocks the distillation operation.

It has now been discovered that this difliculty may be overcome providing the concentration of the quinone in the water condensate is kept below saturation, and preferably well below saturaextent that no cake is formed. This result may be accomplished by condensing the steam in an excess of water which is constantly refreshed, followed by subsequent removal of the quinone from this water'.. From the standpoint of economy, however, it is preferred to recirculate the true because it is impossible to completely remove the quinone therefrom. Preferably, this result is accomplished by removing the water before it has become concentrated or saturated with quinone and removing the quinone, or some of it, from the water by contact with a water immiscible quinone solvent, separating the water therefrom and returning it to the condenser.

.As an example of this invention, quinone is distilled from a reaction mixture by the use of steam and preferably under a vacuum, for ex- 7 ample, such as to order of 60 to C. and the distillate condensed in water from which the quinone is removed with a quinone solvent so that the quinone content of the water is kept so low that there will be no blocking of the condenser and no cake will be formed on the pipe leading into the water.

This result may be accomplished by discharging the quinone vapors beneath a body of water Which is then circulated rapidly into another chamber and then passing it through or in contact with a solvent, and returned to the condensing vessel.

The rapidity of circulation and the volume of Water are, of course, adjusted so that caking is entirely or substantially prevented. These adjustments will, of course, also depend upon the solubility of quinone in the solvent.

The invention is illustrated diagrammatically in the drawing, in which i represents a still containing a reaction mixture 2 into which steam may be supplied by the line 3. The reaction mixwater, and this is particularly produce a temperature of the ture may be such as is obtained by oxidizing aniline with manganese compounds. Distillate passes off through the line t into the condenser 5, the mouth 6 of the line I being within the body of water 1 in the condenser. The water is circulated through the line l2 by the pump I3 into the extraction vessel l5, wherein a layer of solvent is maintained. A cooling coil ['6 may be supplied therein for cooling the solvent. The arrangement shown is for a solvent heavier than water, but where a lighter solvent is used the flow may be reversed. The washed water passes through the line I! controlled by the valve l8 and back to the condenser 55.

A vacuum is maintained within the condenser 5 by the pump Ill, both for the purpose of facilitating the evaporation of quinone in the still and also to cool the water within the condenser by boiling. The boiled water is condensed within the reflux condenser IS. A line 20, controlled by valve 2|, may lead from the solvent vessel I4 to the condenser tubes and may be employed to wash out the condenser of quinone, if necessary, by circulating some of the washed water therethrough. The valves IB and 2| may be kept partially open, if desired, to maintain a higher pressure in the vessel H than in the condenser 5.

This system has the advantage that the solvent need not be subjected to a high vacuum under which it would evaporate and be lost, or would have to be recovered in part through an expensive recovery system. A low boiling solvent is desirable in the subsequent recovery of the quinone. The chamber 15 may even be under pressure if desired. Thus, very low boiling solvents may be employed.

The water in the condenser 5 should be kept slightly acid to prevent decomposition of quinone. The water may be cooled by vacuum induced evaporation.

Any water immiscible solvent may be employed, but preferably it should be one having a high vapor pressure'wherever heat or a high vacuum is employed.

The quinone may then be recovered readily from the solvent and the water.

The invention is, of course, applicable to any other compound, organic or inorganic, which has a tendency to cake in the condenser, and which is volatile with steam.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations should be understood therefrom, but the appended claimsshould be 10 water through a body of solvent to maintain the construed as broadly as permissible in view of the prior art.

I claim:

1. The method of distilling a. quinone which comprises volatllizlng the quinone with steam, condensing the vapors in a body of water in the substantial absence of an organic solvent for the quinone, and continuously extracting the qulnone from the water by circulation of the concentration of the quinone therein at a point so low that it will not form a cake in the condenser.

2. The method as set forth in claim 1, in which the water is cooled by maintenance of a vacuum thereon.

3. The method as set forth in claim 1 in which the quinone is benzoquinone.

' ALWIN' c. CARUS. 

